Skeletal abnormalities caused by disproportioned bone overgrowth (LBO), are a common trait in Marfan syndrome (MFS), a connective tissue disease caused by mutations in the extracellular matrix (ECM) protein and TGFβ regulator fibrillin-1 (Fbn1). The cause of LBO in MFS is unknown and therapies are not available. Fibrillin-1 hypomorphic mouse model (Fbn1mgR/mgR) faithfully replicates MFS skeletal manifestations including elongated bones however, its early demise due aortic rupture limit the magnitude of LBO investigation. To circumvent Fbn1mgR/mgR lethality and investigate the contribution of specific skeletal tissues to LBO, Fbn1 gene expression was targeted in developing limbs by crossing Fbn1Lox/Lox mice with Prx1-Cre, in or bone with Osx-Cre, in cartilage and perichondrium with Col2-Cre, in skeletal muscles with Mef2c-Cre, and ligaments and tendons with Scx-Cre. Bones length of Fbn1 conditional mice KO was measured and relevant histological, cellular and biomechanical parameters were assessed.Introduction
Materials and Methods